Final answer:
The orbitals that overlap for Br2 and have the same electron configuration as a noble gas are 4p and 4p orbitals, forming a σ bond. The 4p orbitals of each bromine atom share an electron, resulting in a configuration similar to the noble gas krypton.
Step-by-step explanation:
For the molecule Br2, the overlapping orbitals that give it a similar electron configuration to that of a noble gas are 4p and 4p orbitals. These orbitals overlap end-to-end to form a σ bond. Each bromine atom has an electron configuration that ends in 4s24p5. When the two bromine atoms bond, they each share an electron filling their respective 4p orbitals, which results in a configuration that mimics the noble gas krypton (Kr) with an electron configuration 4s24p6.
Additional information on electron orbitals:
Atomic radius tends to decrease as effective nuclear charge increases; thus, the smallest atomic radius would likely belong to 4s24p3 due to its higher energy level and additional protons. In bonding, σ bonds are always formed by end-to-end overlap of orbitals, such as a 4p and 4p orbital, while π bonds result from side-by-side overlap. For the hybridization of carbon, sp3 hybrid orbitals are formed when one s and three p orbitals mix, leading to a tetrahedral arrangement as in methane (CH4).